Radio terminals in a wireless communications network communicate with one or more core networks via a Radio Access Network (RAN). The radio terminals may e.g. be mobile stations or user equipment units such as mobile telephones also known as “cellular” telephones, and laptops with wireless capability, e.g., mobile terminals, and thus can be, for example, portable, pocket, hand-held, computer-comprised, or car-mounted mobile devices which communicate voice and/or data with radio access network.
A radio access network covers a geographical area which is divided into cell areas, with each cell area being served by a radio access node, e.g. a Radio Base Station (RBS). In some radio access networks the radio access node may e.g. be called “NodeB” or “B node” or enhanced NodeB (eNB). A cell is a geographical area where radio coverage is provided by the equipment of a radio access node at a radio access node site. Each cell is identified by an identity, which may be broadcasted by the radio access node in within the local cell area. The radio access nodes communicate via an air interface with the radio terminals within range of the radio access nodes.
In some radio access network, several radio access nodes are connected, e.g. by landlines or microwave links, to a Radio Network Controller (RNC) or a Base Station Controller (BSC) or similar, which supervises and coordinates various activities of the plural base stations connected thereto. A RNC or a BSC or similar are typically connected to one or more core networks.
For example, the Universal Mobile Telecommunications System (UMTS) is a third generation wireless communication system, which evolved from the Global System for Mobile Communications (GSM), and is intended to provide improved mobile communication services based on Wideband Code Division Multiple Access (WCDMA) technology. UMTS Terrestrial Radio Access Network (UTRAN) is essentially a radio access network using wideband code division multiple access for user equipment units (UEs). The Third Generation Partnership Project (3GPP) has undertaken to evolve further the UTRAN and GSM based radio access network technologies. Long Term Evolution (LTE) together with Evolved Packet Core (EPC) is the newest addition to the 3GPP family.
In modern wireless communication systems there are typically Service Aware Charging and Control (SACC) components like an Online Charging System (OCS) and/or a Policy and Charging Rules Function (PCRF) that requires information about the location of the radio terminals in the system. The main purpose is to enable a differentiation of charging and policy depending on the location of a radio terminal.
For example, in LTE the PDN Gateway (PGW) reports changes in location of a radio terminal to the PCRF. In turn, the PDN Gateway (PGW) may request the Mobility Management Entity (MME) to report changes in location of a radio terminal, e.g. by report changes of ECGI/TAI by independently using the “MS Info Change Reporting Action” parameter for any or each Packet Data Network (PDN) connection of a User Equipment (UE) and/or to report changes of user CSG information by using the “CSG Information Reporting Action” parameter.
However, this causes a heavy signalling load from the MME via the Serving Gateway (SGW) to the PGW, and from the PGW to the PCRF. Due to the increased signalling load it is recommended that a report of change in location is only applied for a limited number of radio terminals. However, even if a change in location is only reported for a limited number of terminals, the signalling load may still be too heavy.